This invention relates to polyether resin compositions, a process for preparation thereof, coating compositions containing said polyether resins, a coating process employing said compositions and cured films obtained by use of these compositions.
European patent specification 3166 discloses a process in which a glycidyl ester of a mixture of C.sub.9-11 branched aliphatic acids was reacted at 100.degree. C. with trimethylolpropane (hereinafter "TMP") in a glycidyl/primary hydroxyl group equivalent ratio of 2:3, in the presence of 0.5% wt based on glycidyl ester, of a boron trifluoride etherate etherification catalyst. However, side reactions between the alcohols, the glycidyl ester, and secondary hydroxyl groups take place in the presence of this boron trifluoride etherate catalyst. With gel permeation chromatography (GPC), the product using the process in the European patent specification has been found to contain several side products. These products are dark colored and contain a high number of compounds in which only one primary hydroxyl group has reacted and a high number of compounds in which all three primary hydroxyl groups have reacted, which is reflected in a combination of relatively high average molecular weight and a broad molecular weight distribution. These products have been found to be less suitable for coating applications because of the undesirable phenomenon of cratering.
It is therefore an object of the invention to provide a process for preparing polyether resins suitable for coating applications. It is another object of the invention to provide a coating free of cratering. It is another object of the invention to provide polyether films which have very good properties suitable for general industrial stoving applications.